Sleep disruption is a recognized and problematic symptom across the anxiety disorders spectrum. Individuals suffering anxiety additionally display a hallmark signature of enhanced amygdala reactivity to aversive stimuli. Independently, sleep loss in healthy participants results in amplified amygdala reactivity, together with raised levels of anxiety, while the beneficial presence of sleep conversely offers a palliative reduction in next-day aversive reactivity and anxiety. Despite these parallel lines of evidence, the relationship between sleep, anxiety and emotional brain reactivity remains uncharacterized. The need to explore this potentially causal interaction is not only imperative for gaining a deeper understanding of the pathophysiological etiology underlying anxiety, but also for the development of improved preventative strategies and effective treatments for amelioration of anxiety. Across separate experiments combining functional MRI (fMRI), sleep EEG recordings and neurobehavioral assessments, this proposal will test the hypothesis that high anxiety status (1) prevents the normal physiological benefit of sleep in regulating next-day amygdala reactivity, (2) imposes greater vulnerability of the amygdala to the aggravating effects of sleep loss, and (3) negates the benefit of recovery sleep in restoring normative amygdala reactivity, following sleep loss. As such, this proposal represents a systematic evaluation of how anxiety status alters the sleep-dependent regulation of optimal emotional brain function, and how a lack of sleep contributes to the amplified neural signature associated with high anxiety status. Understanding the causal associations between anxiety, sleep impairment, and emotional brain reactivity has considerable clinical and public health ramifications, as well as direct translational treatment applicability. Moreover, considering the continued erosion of sleep time across society, particularly in young populations susceptible to anxiety-related emotion difficulties, the applicability of these studies further increases in relevance. PUBLIC HEALTH RELEVANCE: This proposal represents a systematic evaluation of how anxiety alters the sleep- dependent regulation of optimal emotional brain function, and how a lack of sleep contributes to the amplified neural signature associated with high anxiety status. Understanding the causal associations between anxiety, sleep, and emotional brain reactivity has considerable clinical and public health ramifications, as well as direct translational treatment applicability. Moreover, considering the continued erosion of sleep time across society, particularly in young populations additionally susceptible to anxiety-related emotion difficulties, the applicability of these studies further increases in relevance.